Suppress flaky test on macos for CrSettingsMainPageTest.MainPage

chrome/test/data/webui/settings/cr_settings_browsertest.js

Index: chrome/test/data/webui/settings/cr_settings_browsertest.js
diff --git a/chrome/test/data/webui/settings/cr_settings_browsertest.js b/chrome/test/data/webui/settings/cr_settings_browsertest.js
index f2ebd53bdc7f8e5b834002160241a942acceee2b..2218c2c9051c5feb72b30e04dc5facc42d118bb6 100644
--- a/chrome/test/data/webui/settings/cr_settings_browsertest.js
+++ b/chrome/test/data/webui/settings/cr_settings_browsertest.js
@@ -937,7 +937,8 @@ TEST_F('CrSettingsRouteDynamicParametersTest', 'MAYBE_All', function() {
 
 // Times out on Windows Tests (dbg). See https://crbug.com/651296.
 // Times out / crashes on chromium.linux/Linux Tests (dbg) crbug.com/667882
-GEN('#if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(OS_LINUX)');
+GEN('#if defined(OS_WIN) || defined(OS_CHROMEOS) || defined(OS_LINUX)' +
+    ' || defined(OS_MACOSX)');
 GEN('#define MAYBE_MainPage_All DISABLED_All');
 GEN('#else');
 GEN('#define MAYBE_MainPage_All All');